An order of n = 3,000 transistors is received. The probability that each transistor is defective is p = 0.001. What is the probability that the number of defective transistors in the batch is 6 or less?
P(0)= $${{\mathtt{0.999}}}^{{\mathtt{3\,000}}} = {\mathtt{0.049\: \!712\: \!393\: \!998\: \!036\: \!3}}$$
P(1)= nCr(3000,1)*0.001*0.999^2999
P(2)= nCr(3000,2)*0.001^2*0.999^2998
P(3)= nCr(3000,3)*0.001^3*0.999^2997
P(4)= nCr(3000,4)*0.001^4*0.999^2996
P(5)= nCr(3000,5)*0.001^5*0.999^2995
P(6)= nCr(3000,6)*0.001^6*0.999^2994
work those out and add them up.
this calc was baulking - might do better in Wolfram|Alpha calcualtor
P(0)= $${{\mathtt{0.999}}}^{{\mathtt{3\,000}}} = {\mathtt{0.049\: \!712\: \!393\: \!998\: \!036\: \!3}}$$
P(1)= nCr(3000,1)*0.001*0.999^2999
P(2)= nCr(3000,2)*0.001^2*0.999^2998
P(3)= nCr(3000,3)*0.001^3*0.999^2997
P(4)= nCr(3000,4)*0.001^4*0.999^2996
P(5)= nCr(3000,5)*0.001^5*0.999^2995
P(6)= nCr(3000,6)*0.001^6*0.999^2994
work those out and add them up.
this calc was baulking - might do better in Wolfram|Alpha calcualtor